var HttpClient = function () {
  this.get = function (aUrl, aCallback) {
    var anHttpRequest = new XMLHttpRequest();
    anHttpRequest.onreadystatechange = function () {
      if (anHttpRequest.readyState == 4 && anHttpRequest.status == 200)
        aCallback(anHttpRequest.responseText);
    };

    anHttpRequest.open("GET", aUrl, true);
    anHttpRequest.send(null);
  };
};
